A little PHD help please

[Woody]

Hello all

I am trying to get PHD working with my 9x50 guidescope via pulse guiding. I have the QHY5 connected via USB and no ST4 cable.

Here is what I am doing

1. Start PHD, connect camera and mount ("ASCOM" not "On camera")

2. Start looping, select star (not a hot pixel) and press the guide button

3. PHD then starts to calibrate west and after about 40 steps gives up saying that there is no movement.

I have increased the calibration step to 2000ms ( have tried lower number also) but still nothing. Every other setting is on default.

I am 100% sure I am selecting stars and not hot pixels also.

In EQMOD should I turn off the sidereal tracking when I start PHD?

It seems that because sidereal is on and is tracking well that there is not enough movement for PHD to start working.

I am a little bit stumped and confused?

Thanks for reading

Jeremy

[malc-c]

Due to the short focal length of the finder, my guess is that the stars appear small on the sensor and thus there is little movement to detect. Try increasing the calibration steps to 3000 - 4000ms and see if that helps

leave the mount tracking, and for calibration choose a large bright stars

[Woody]

Thanks Malcolm, I have just set up so will try that out.

Cheers

[bamus]

I would also recommend increasing calibration step to minimum 3000 and try to make calibration on the star near declination 0. Sometimes it is hard to perform calibration if you are trying to do it close to poles (dec 75-90)

You can also check if in PHD “Disable guide output” in un ticked

[Woody]

Thanks bamus, I am experimenting as we speak (or type!)

[chrisshillito]

The mount's response to autoguiding signals varies with target declination and so calibration really needs to performed on the guide star you intend to use during image capture (and which I would assume is close to your target). The fact that stars around the pole rquire appear to move much slower in response to mount movement is something phd needs to learn as part of calibration. You can't therfore calibrate at an arbitary declination, such as 0, and expect phd to guide sucessfully on a target around the pole (phd will under correct).

Chris

[ianaiken]

I would also recommend that you knock the finder out of focus a bit, this will increase the star size and helps with calibration. On my setup I can calibrate with a step size of 1500 although it takes quite a while. I may actually increase this after reading the above.

[terrym2002uk]

You may also want to reduce min motion down to around 0.05 - 0.06 or so as a small movement of the star in your guidescope might be quite a large movement in your imaging scope.

Also make sure you have ASCOM set for the telescope control if you are using EQMOD for pulse guiding. Leave the pulse guide set around 0.5 in EQMOD for starters.

[swag72]

Here's the settings that I used with my 9x50 guider and QHY5. Used to get me a nice flat graph. Hope that helps. May give you a starting point.

[Woody]

That is all really great, thanks very much everyone for the excellent advice.

I got it all working last night (until the dew took over!) and I am processing my images this morning.

Thanks again

Jeremy

[terrym2002uk]

That's great.

What settings did you end up using, as this may help others with a similar configuration.

[Woody]

That's great.

What settings did you end up using, as this may help others with a similar configuration.

I played around a fair bit and increased the calibration steps to 3000/3500ms, everything else (for the moment) is set to default values.

Cheers